1. Field of the Invention
The present application relates to a display device, and more particularly, to a three-dimensional image display device having a pivot function without deterioration in color display and a method of driving the three-dimensional image display device.
2. Discussion of the Related Art
Recently, according to a user's request for a display device displaying a three-dimensional image having an actual feeling, three-dimensional display devices have been researched and developed. In general, a stereoscopic image expressing a three-dimension is displayed using a principle of stereovision through eyes. Accordingly, liquid crystal display (LCD) devices that display an image of a stereoscopic effect using a binocular disparity due to a separation distance of eyes, e.g., about 65 mm have been suggested. When distinct two-dimensional images of a three-dimensional image display device are viewed to right and left eyes, respectively, the distinct two-dimensional images are transmitted to a brain and are combined to a three-dimensional image having depth effect and reality by the brain. This phenomenon may be referred to as a stereography.
There are various types of three-dimensional image display devices, for example, a stereographic type using specific glasses, a stereoscopic type without using and a holographic type. The stereoscopic type three-dimensional image display devices using specific glasses may include a polarization glasses type using an oscillation direction or a rotation direction of a polarized light, a time division glasses type where right-eye and left-eye images are alternately viewed and a density difference type where images having different brightness are viewed to right and left eyes, respectively. In addition, the stereoscopic type three-dimensional image display devices without using glasses may include a parallax barrier type where distinct two-dimensional images are divided by an aperture of a vertical lattice shape and are viewed to right and left eyes, respectively, a lenticular type using a lenticular plate where cylindrical lenses are arranged in stripe, and an integral photography type using a lens plate having a fly eye shape. Furthermore, the holographic type three-dimensional image display device where perfect three-dimensional images having a focus adjustment, a binocular parallax and a movement parallax for stereoscopy are obtained may include a laser light regenerated hologram type and a white light regenerated hologram type.
Among the various types of three-dimensional image display device, a parallax barrier type three-dimensional image display device has been widely used. FIG. 1 is a view showing a three-dimensional image display device according to the related art. In FIG. 1, a three-dimensional image display device 11 of a parallax barrier type includes a display panel 11 and a parallax barrier 30 over the display panel 11. The display panel 11 displays right-eye and left-eye images, and the parallax barrier 30 has slits arranged horizontally or vertically. The parallax barrier 30 blocks the right-eye image for left eye and the left-eye image for right eye so that the right-eye and left-eye images can be transmitted to the right and left eyes, respectively. As a result, a three-dimensional image resulting from the combination of the right-eye and left-eye images using the binocular parallax is displayed to a user.
Recently, a three-dimensional image display device including a parallax barrier of a mosaic shape has been suggested. In addition, the three-dimensional image display device may have a pivot function such that three-dimensional images are displayed in a landscape mode or a portrait mode. Accordingly, the three-dimensional image display device may display the three-dimensional images when a longer axis of the display panel is arranged along horizontal and vertical directions.
FIG. 2 is a plan view showing a three-dimensional image display device according to the related art. FIG. 2 corresponds to one of a right-eye image viewed to a right-eye and a left-eye image viewed to a left-eye. In FIG. 2, a three-dimensional image display device 50 of a parallax barrier type includes a display panel 60 and a parallax barrier 70 over the display panel 60. The display panel 60 includes a plurality of pixels P each having red (R), green (G) and blue (B) sub-pixels SP. The red, green and blue colors are arranged in a vertical stripe type such that red, green and blue colors are alternately disposed along a horizontal direction H and each of red, green and blue colors is disposed in a single line along a vertical direction V. The adjacent red, green and blue sub-pixels SP of the single pixel P have one of the right-eye and left-eye images. The parallax barrier 70 has a plurality of open areas OA surrounded by a blocking area BA. The plurality of open areas OA are arranged in a mosaic shape such that the open area OA and the blocking area BA are alternately disposed with each other as in a chess board. Each pixel P corresponds to the single open area OA, and the up, down, right and left pixels P adjacent to the pixel P corresponding to the single open area OA correspond to the blocking area BA. In addition, the up, down, right and left pixels P adjacent to the single pixel P corresponding to the blocking area BA correspond to the plurality of open areas OA.
A user may watch the three-dimensional image display device at a front position or at a slanting position. Alternatively, the three-dimensional image display device may display images in a landscape mode or a portrait mode. When the open area OA of the parallax barrier 70 has the same area as the pixel P of the display panel 60, both the right-eye and left-eye images are transmitted to one of the right and left eyes of a user at the slanting position, thereby a display quality deteriorated. Accordingly, an area of the open area OA is substantially smaller than an area of the pixel P including the red, green and blue sub-pixels SP so that the right-eye and left-eye images can be transmitted to the right and left eyes, respectively. As a result, the deterioration in display quality is prevented.
FIG. 3 is a plan view showing an open area and a blocking area of a three-dimensional image display device according to the related art. In FIG. 3, a three-dimensional image display device 50 of a parallax barrier type includes a display panel 60 and a parallax barrier 70 over the display panel 60. The display panel 60 includes a pixel P having red (R), green (G) and blue (B) sub-pixels SP. Each sub-pixel SP has a first side parallel to a horizontal direction H and a second side parallel to a vertical direction V. A length 3 p of the second side is about three times of a length p of the first side. The parallax barrier 70 includes an open area OA at a center portion of the pixel P and a blocking area BA surrounding the open area OA. Accordingly, the blocking area BA has a rectangular ring shape including first to fourth side rings. Each of the first and third side rings of the blocking area BA parallel to the horizontal direction H has a first width d1 and each of the second and fourth side rings of the blocking area BA parallel to the vertical direction V has a second width d2. The first and second widths d1 and d2 may be about 5% to about 10% of the length 3 p of the second side of each sub-pixel SP (d1, d2=0.05*(3 p)˜0.1*(3 p)=0.15 p˜0.3 p). As a result, an area ratio of the open area OA (from (3 p−2*(0.3 p))2=(2.4 p)2=5.76 p2 to (3 p−2*(0.15 p))2=(2.7 p)2=7.29 p2) to the pixel P (9 p2), i.e., an aperture ratio is within a range of about 64% to about 81%.
In the three-dimensional image display device according to the related art, since the spatial distribution of colors is different in the red, green and blue sub-pixels SP, a valid viewing zone where a three-dimensional image is viewable is restricted. For example, when the three-dimensional image display device operates in a landscape mode where the red, green and blue sub-pixels SP are alternately disposed along the horizontal direction H, the color distribution may be changed by horizontal movement of a user and the resultant color property of the three-dimensional image may be deteriorated.
FIGS. 4A and 4B are plan views showing a three-dimensional image display device according to the related art. FIGS. 4A and 4B correspond to one of a right-eye image viewed to a right eye and a left-eye image viewed to a left eye when a user moves left and right, respectively.
In FIG. 4A, when a three-dimensional image display device 50 is viewed to a user having moved left, a parallax barrier 70 may be viewed to be shifted right with respect to a display panel 60. A portion of a blue sub-pixel SP exposed through an open area OA of the parallax barrier 70 is enlarged and a portion of a red sub-pixel SP exposed through the open area OA of the parallax barrier 70 is reduced, while a portion of a green sub-pixel SP is kept constant without change. As a result, the three-dimensional image may have a bluish color. In FIG. 4B, when the three-dimensional image display device 50 is viewed to a user having moved right, the parallax barrier 70 may be viewed to be shifted left with respect to the display panel 60. A portion of the blue sub-pixel SP exposed through the open area OA of the parallax barrier 70 is reduced and a portion of the red sub-pixel SP exposed through the open area OA of the parallax barrier 70 is enlarged, while a portion of the green sub-pixel SP is kept constant without change. As a result, the three-dimensional image may have a reddish color. Accordingly, color display quality of the three-dimensional image is deteriorated and a valid viewing zone is restricted.